Masterparts has a comprehensive range of automotive timing belt tensioners and idler wheels for sale at branches across South Africa and in Namibia.
What does the timing belt tensioner and idler wheels do in a car?
The timing belt tensioner and idler wheels are critical components in a vehicle’s drive system.
Together the parts maintain optimal tension and alignment of the timing belt as it rotates through the engine to power the ancillary components – the alternator, power steering pump, air conditioner compressor and water pump.
A tensioner with an automotive timing belt (Source: Una Smith, under CC BY 3.0).
When either of the parts are worn or damaged, the timing belt can slip and the engine can fail.
Timing belt tensioners can be mechanical or hydraulic. They are available in various shapes and sizes and manufactured from a range of metal and polymer materials.
Idler wheels are typically made from hardened steel, plastic, rubber or aluminium. The size and shape varies according to application.
A timing belt being installed. The round unit below the camshaft pulley is an idler wheel. (Source: Petar Milošević, CC BY-SA 3.0, via Wikimedia Commons).
Timing belt tensioners and idlers wheels are alternatively known as tensioner and idler pulleys or tensioner and idler bearings.
How do timing belt tensioners and idler wheels work?
In most vehicles, the timing belt tensioner is located at one end of the timing belt and locked in place with a bolt.
Depending on the type of tensioner, a mechanical spring or hydraulic piston is used to maintain the tautness of the belt.
Modern cars typically have a hydraulic timing belt tensioner. The part consists of a main housing containing the hydraulic system, tensioner pulley or bearing, and lever.
For an inside view of a hydraulic timing belt tensioner, we recommend the illustration at Mechanic.com.au.
When the engine is off, the spring applies sufficient tension to prevent the belt from slipping. As the engine starts, the crankshaft rotates and the timing belt begins its journey through the engine, guided by the idler wheels.
The movement of the belt pushes the piston located inside the housing. At that point, hydraulic fluid (oil) fills the chamber behind the piston, generating the pressure required to force the piston up.
This hydraulic pressure is then used by the tensioner to adjust the tautness of the belt in response to the dynamic engine conditions.
Idler wheels are also bolted to the engine. They have a smooth surface with a groove running along one end to hold the timing belt in place.
These components direct the path of the belt from one pulley to the next.
Signs of a worn timing belt tensioner or idler wheels
Timing belt tensioners and idler wheels are subjected to extreme engine conditions. Over time, they can wear and fail.
Signs of wear or damage include squealing noises when starting the engine or turning the steering wheel, a misfiring engine or rattling sounds from under the bonnet.
The car’s performance is generally affected, and the check engine light on the dash is usually on.
Where to get timing belt tensioners and idler wheels from Masterparts
We offer a comprehensive range of timing belt tensioners and idler wheels for different vehicle makes and models.
Timing belt tensioners and idler wheels in and around Cape Town:
Timing belt tensioners and idler wheels in KwaZulu-Natal:
Timing belt tensioners and idler wheels in Namibia:
Along with timing belt tensioners and idler wheels, Masterparts supplies a full range of suspension, steering, engine, braking and electronic parts for cars. Contact us if there’s a part you need and we’ll do our best to help.
